High fruit and veggie diet linked to lower risk of heart disease, death

NEW YORK (Reuters Health) - Researchers have more evidence
linking a diet with lots of fruits and vegetables to better
health outcomes.

The idea that fruits and veggies are good for you isn't new,
of course. What's new in this study is that researchers saw a
dose-response relationship: the more fruits and veggies people
ate, the less likely they were to have heart problems or die
while researchers were studying them.

The protective effects of fruits and veggies leveled out at
five servings per day, which supports current dietary
recommendations, senior author Dr. Frank B. Hu, of the
departments of nutrition and epidemiology at the Harvard School
of Public Health in Boston, told Reuters Health by email.

The findings are from a fresh analysis of 16 existing
studies that involved more than 800,000 people. The studies
lasted at least four years, and sometimes up to 26 years. Around
56,000 participants died during the studies.

Six studies included data on vegetables in the diet over
time, six examined fruits, and four included both. The studies
were conducted in the U.S., Asia and Europe.

Compared to people who ate no fruits or vegetables, those
who ate one serving per day were roughly five percent less
likely to die of any cause over the course of the studies. And
with every additional serving, the risk of death decreased by
another five percent, according to the combined analysis
published in BMJ.

The risk of dying from heart disease decreased with more
fruits and vegetables in a similar way, but the risk of dying
from cancer did not appear to change.

More than five servings of fruits and vegetables daily
didn't confer any additional benefit.

Most of the studies took into account people's age, body
mass index, smoking and alcohol consumption, which can all
affect the risk of dying from heart disease or other problems.
But since it only included observational studies, the review
can't prove that these dietary habits will protect people from
heart disease and death, only that the two are connected. People
in the studies could have been making other lifestyle choices
that would influence the results.

It would not be feasible to do a randomized controlled trial
on consumption of fruits and vegetables because it would involve
thousands of people eating the same diets for many years, Hu
said. In the absence of those, large prospective cohort studies
like the ones he looked at are the best available evidence, he
said.

Randomized trials have found a connection between a
generally healthy diet and delayed onset of heart disease, Hu's
coauthor Wei Bao told Reuters Health by email.

"For instance, the Lyon Diet Heart Study and the PREDIMED
study have shown a significant reduction of cardiovascular
events by a Mediterranean-style dietary pattern which includes a
large amount of fruits and vegetables," said Bao, a postdoctoral
fellow at the Eunice Kennedy Shriver National Institute of Child
Health and Human Development at the National Institutes of
Health in Rockville, Maryland.

The vitamins, minerals, fiber and phytochemicals found in
fruits and vegetables may improve blood lipids and blood
pressure and reduce insulin resistance and chronic inflammation,
Hu said.

Eating more than five servings daily may confer benefits in
other areas, like stroke risk, and even if it does not, there is
no evidence of harm from a high-plant diet, he said.

"Since the average consumption of fruits/veggies in the
general population is far below five servings per day, there is
still a long way to go before meeting the recommended intakes,"
Hu said.

They did not look at individual fruits and vegetables, and
more research will be needed to examine the health effects of
specific foods in this category, he said.